Adjustable joist



Nov. 1, 1955 A. s. T. LAGAARD ADJUSTABLE JOIST Filed April 17, 1950 RAVIALEXANDER S.T. LAGAARD' NV E N R gmwp g mmmgvs United States PatentADJUSTABLE JOIST Alexander S. T. Lagaard, Minneapolis, Minn., assignorto Richard F. Tickle, Minneapolis, Minn.

Application April 17, 1950, Serial No. 156,280

11 Claims. (Cl. 189-37) The herein disclosed invention relates toadjustable joists and particularly to the type having adjacent joistsections each constructed with an upper and a lower chord and withdiagonal truss members therebetween and has for an object to provideadjusting means between the chords whereby the length of the joist maybe varied.

Another object of the invention resides in providing adjusting meansbetween the upper chords of the joist sections whereby the camber of thejoist may be varied.

Another object of the invention resides in constructing the adjoiningends of the upper chord of the two adjacent chord section withcooperating parts utilizing eccentrics movable to vary the spacing ofthe chords.

A still further object of the invention resides in constructing theupper chords of the adjacent sections with depending flanges havingslots therein, in disposing along said flanges plates having holesadapted to register with said slots and in further providing boltsextending through said holes for clamping the parts together.

An object of the invention resides in constructing some of said boltswith eccentrics engageable with said slots, said bolts upon rotationserving to vary the spacing between the upper chords and thus varyingthe camber of the joist.

Other objects of the invention reside in the novel combination andarrangement of parts and in the details of construction hereinafterillustrated and/or described.

In the drawings has been illustrated a portion of a joist including oneend section and a part of one intermediate section. These sections areconstructed in the form of trusses and have upper and lower chords, withdiagonal chord members therebetween. The lower chords of adjacentsections are connected together by means of plates bolted to the flangesthereof. These plates and the flanges of the lower chords have a numberof holes in them whereby the sections may be bolted together to vary thelength of the truss by increments depending upon the spacing of theholes. The upper chords of adjacent sections have flanges depending fromthe webs of said chords and lying in continuation of one another. Inthese flanges are formed adjacent the adjoining ends of said flangesvertical slots. Outwardly from the vertical slots are formed in saidflanges horizontal slots. Overlying these flanges are two plates whichare constructed with holes registering with the slots of said flanges. Anumber of bolts extend through these holes and clamp the parts together.The two bolts extending through the vertical slots are constructed witheccentrics adapted to vary the spacing of the ends of the upper chordand thus vary the camber of the joist.

In the drawings:

Fig. 1 is an elevational view of a portion of a joist illustrating anembodiment of the invention.

Fig. 2 is a view of a portion of the structure shown in Fig. 1 withparts broken away and drawn to a greater scaler "ice Fig. 3 is a planview of the portion of the upper chord of the truss shown in Fig. 2 withportions thereof broken away to show the construction of the attachingmeans therefor.

Fig. 4 is a view similar to .Fig. 2 showing the parts in adjustedposition.

Fig. 5 is a view similar to Fig. 4 with the parts disposed to provide atruss of greater length.

Fig. 6 is a perspective .view of one of the bolts having the eccentricformed thereon and used with the invention.

Fig. 7 is a perspective view of one of the other bolts of the invention.

The joist illustrated in the drawings has been designated in itsentirety by the reference numeral A and consists of two joist sections Band C. The section C is an intermediate section while the section B isan end section. It will readily be comprehended that another endsection, similar to section B will be employed, that the section C willbe the same at both ends and that other sections similar to section Cmay be utilized if found desirable.

The joist section C comprises an upper chord 10 and a lower chord 11arranged in parallel relation. These chords are constructed fromstructural members T- shaped in cross section and which have flanges 12and 13 and webs 14 and 15 facing one another and with the flanges 12 and13 outermost. Between the webs 14 and 15 are arranged diagonal trussmembers 16 which are constructed from a single rod 17 provided withbends 18 and which form the truss members 16. The bends of said rods arewelded to the webs 14 and 15 or may be secured thereinto in any suitablemanner. The diagonal truss members 16 terminate short of the ends 19 and20 respectively of the chords 10 and 11 as best shown in Fig. 1 for apurpose which will presently become apparent.

The end joist section B is constructed similar to the joist section Cand consists of an upper chord 21 and a lower chord 22. These chords arealso constructed of structural members T-shaped in cross section andhave flanges 23 and 24 and webs 25 and 26. These chords are arrangedwith the webs 25 and 26 extending toward one another and are disposed inalignment with the chords 11 and 12. Diagonal truss members 27 extendbetween the chords 21 and 22 and are similar to the truss members 16being constructed from a rod 28 formed with bends 29 which are welded tothe webs 25 and 26 of the chords 21 and 22. The lower chord 22 is formedwith bends 30 and 31 which form in said lower chord an upwardly inclinedmember 32 and a horizontal portion 133 which lies adjacent the upperchord 21. These v parts are welded to spacers 166 to form a bearing bymeans of which the joist may be supported on the supporting structure.The ends of the chords 22 and 23 of this joist section are indicated bythe reference numerals 35 and 36 respectively.

Between the chords 10 and 21 of the truss section C and B is provided aconnection 33 and between the chords 11 and 22 is provided a connection34. The connection 34 permits of adjusting the length of the truss A bycertain increments. The connection 33 likewise permits of adjusting thelength of the truss by certain increments but in addition permits offurther adjusting the chord to procure the desired camber therein.

The connection 34 consists of a plate 37 which underlies the end 20 ofthe chord 11 and the end 36 of the chord 22. This plate fits up againstthe underside of the flanges 13 and 24 of said chords. On the uppersides of these flanges are aranged bars 39 which are of the same lengthas the plate 37. The bars 39, the flanges 24 and 13 and the plate 37 allhave registering holes 40 therein.

Bolts 41 may be inserted through the said holes and nuts 142 screwed onsaid bolts clamp the parts together. The holes 40 are spaced equaldistances apart in all of the flanges, plates and bars so that the trusssections may be extended to different lengths and the bolts insertedthrough the appropriate holes to give the desired lengths.

The connection 33 consists of two plates 42 and 43 which are welded tothe webs 25 and 14 respectively of the chords 21 and and which formextensions of said webs constituting flanges depending therefrom. Theseflanges have vertically extending slots 44 and 45 formed in the same anddisposed close to the ends of the chords 21 and 10. The said flangeshave a number of horizontal slots 46 and 47 which are disposedsubstantially in alignment and which are spaced apart the same distanceas the spacing of the holes 40. Overlying the flanges 42 and 43 are twoplates 48 and 49. These plates have holes 50 and 51 in the same whichare adapted to register with the slots 44, 45, 46 and 47. The holes 50are larger than the holes 51 for a purpose to be presently explained.

Extending through the slots 44 and 45 in the flanges 42 and 43 andthrough the corresponding holes 50 and 51 in the plates 48 and 49 arebolts 52, one of which is shown in detail in Fig. 6. This bolt has ahead 53 either hexagonal as shown or square and is formed with a collar54 adjacent said head and of a size to be snugly received in any of theholes 50 of plate 48. Adjacent this collar the bolt is formed with aneccentric 55 which is of lesser diameter than the collar 54 and which iseccentrically disposed with reference to the axis of said collar. Theouter element of this eccentric may lie in alignment with thecorresponding element of the collar 54 so as to give the maximumpossible throw to the eccentric. Issuing outwardly from the eccentric 55is a shank 56 which is threaded as indicated at 57 to receive a nut 58.The shank 56 is concentric with the collar 54 and it likewise has itsouter element lying in continuation of the corresponding element of theeccentric 55. By means of this construction the shank 56 is of maximumdiameter to give the maximum strength to the bolt. The shank 56 issnugly received in the holes 51 of plate 49. It will be readilycomprehended When the bolts 52 are rotated that the eccentrics 55 engagethe vertical walls 59 of the slots 44 and 45 and procure relativemovement between the plates 48 and 49 and the flanges 42 and 43. Thiscorrespondingly produces relative movement between the ends 19 and 35 ofthe chords 10 and 21 and varies the camber of the joist.

Extending through the slots 46 and 47 of the flanges 42 and 43 are bolts60, one of which is shown in detail in Fig. 7. This bolt has a head 61similar to the head 53 of bolt 52 and a collar 62 adjoining said headand of the same diameter and length as the collar 54 of bolt 52.concentric with the collar 62 and having threads 64 formed thereon. Thecollar 62 is adapted to fit in any of the holes of the plate 48 whilethe shank 63 is adapted to fit in any of the holes 51 in plate 49 andalso in any of the slots 46 and 47 of the flanges 42 and 43. It will benoted that these slots are of a width substantially equal to thediameter of the shanks 63 so that the plates 48 and 49 are properlysupported with reference to the flanges 42 and 43 and restrained fromvertical movement relative thereto. Nuts 65 are screwed on the ends ofthe shanks 63. Between the heads 53 and 61 of the bolts 52 and and theplate 41 are disposed washers 66. Similar washers 67 are disposedbetween the nuts 58 and screwed on said bolts and the plate 49. Thesewashers increase the bearing area against the said plates and permit oftightening up the bolts without marring the plates.

The use of the invention is obvious. If the truss is to be of minimumlength the parts are assembled as shown in Fig. l, 2 and 3. The nuts 142are first tightened up Issuing outwardly from this collar is a shank 63on the bolts 41 and the lower chords 11 and 22 rigidly held secured toone another. The nuts 58 and 65 are then loosened and the two bolts 52rotated until the desired camber is procured. In the rotating of saidbolts the eccentrics 55 move up and down in the slots 44 and 45 whilethe shank 63 of bolts 60 slide horizontally in the slots 46 and 47. Whenthe desired camber has been procured the nuts 58 and 65 are tighteneddown and the entire structure becomes rigidly tied together.

The advantages of the invention are apparent. The camber of the joistcan be easily adjusted within the limits of the eccentric employed.Ordinary wrenches may be used for assembling the parts and for procuringadjustment. The truss is extremely rigid and will support appreciableloads. If desired, adjustment of the camber can be procured after thejoist has been loaded thus permitting of eliminating sag in floors orother structure supported on the truss. The invention can bemanufactured at a nominal expense and will function indefinitely withoutappreciable wear. The invention is positive in action and foolproof inoperation.

Changes in the specific form of the invention, as herein described, maybe made within the scope of what is claimed without departing from thespirit of the invention.

Having described the invention, what is claimed as new and desired to beprotected by Letters Patent is:

1. In an adjustable joist, two joist sections disposed end to end, eachcomprisng upper and lower chords and diagonal truss memberstherebetween, a connection for connecting the lower chords of thesection together, the upper chord of one of said sections having a partformed with a transverse slot therein, a clamp member overlying saidpart and secured to the upper chord of the other truss section, and aneccentric rotatable relative to said clamp member and extending throughsaid slot, said eccentric engaging a wall of said part at the slot toshift the ends of the upper chords relative to one another in alongitudinal direction and clamping means for clamping said clamp memberand part together.

2. In an adjustable joist, two joist sections disposed end to end, eachcomprising upper and lower chords and diagonal truss memberstherebetween, a connection for connecting the lower chords of thesection together, the upper chords of said sections having parts formedwith transverse slots therein, a clamp member overlying said parts,eccentrics rotatable relative to said clamp member, and extendingthrough said slots, said eccentrics engaging opposite walls of saidslots to shift the ends of said upper chords relative to one another ina longitudinal direction and clamping means for clamping the parts andclamp member together.

3. In an adjustable joist, two joist sections disposed end to end, eachcomprising upper and lower chords and diagonal truss memberstherebetween, a connection for connecting the lower chords of thesection together, the upper chord of one of said sections having a.flange extending along the same and formed with a transverse slottherein, a plate overlying said flange and secured to the upper chord ofsaid other truss section, said plate having a round hole thereinoverlying said slot, an eccentric disposed in said slot and having acollar received in said hole, and clamping means for clamping the partstogether.

4. In an adjustable joist, two joist sections disposed end to end, eachincluding upper and lower chords, a connection for connecting the lowerchords of the section together, the upper chord of one of said sectionshaving a flange extending along the same and formed with a transverseslot therein, plates overlying said flange on opposite sides thereof andsecured to the upper chord of said other truss section, said plateshaving circular holes therein registering with one another and with saidslot, the hole in one of said plates being greater in diameter than thehole in the other of said plates, a bolt extending through said holesand slot, said bolt having a head disposed adjacent to the plate havingthe larger hole, a collar on said bolt received in the larger hole, aneccentric on said bolt disposed within said slot, a threaded shankextending outwardly from said eccentric, coaxially disposed withreference to said collar and extending through said smaller hole, a nutscrewed on the end of said shank, said nut and bolt holding saideccentric in adjusted position and assisting in clamping said plates inposition on said flange and other clamping means acting between saidplates for further clamping said plates in position on said flange.

5. In an adjustable joist, two joist sections disposed end to end, eachincluding upper and lower chords, a connection for adjustably connectingthe lower chords of the sections together, the upper chords of saidsections having aligning longitudinally extending flanges thereon, theflange of one of said upper chords having a transverse slot therein anda plurality of longitudinal slots, said slots being spaced equaldistances from one another, plates overlying both of said flanges anddisposed one on each side thereof, said plates having circular holestherein registering with the various slots in said flanges, the holes inone of said plates being greater in diameter than the holes in the otherplate, the holes in each of said plates respectively being ofsubstantially the same diameter, a bolt extending through saidtransverse slot and through the holes registering therewith, other boltsextending through the other registering holes and slots, collars formedon all of said bolts and received in said larger holes, threaded shankson said bolts adapted to extend through any of said smaller holes, headson said bolts adjacent said collars, nuts screwed on the ends of saidshanks, an eccentric on the bolt received in said transverse slot, theshanks of the other bolts being received in said longitudinal slots andmeans for securing said plates to the flange of the upper chord of saidother joist section.

6. In an adjustable joist, two joist sections disposed end to end, eachincluding upper and lower chords, a connection for adjustably connectingthe lower chords of the sections together, the upper chords of saidsections having aligning longitudinally extending flanges thereon, theflange of one of said upper chords having a transverse slot and aplurality of longitudinal slots, said slots being spaced equal distancesfrom one another, plates overlying both of said flanges and disposed oneon each side thereof, said plates having circular holes thereinregistering with the various slots in said flanges, the holes in one ofsaid plates being greater in diameter than the holes in the other plate,a bolt extending through said transverse slot and through the holesregistering therewith, other bolts extending through the otherregistering holes and slots, collars formed on all of said bolts andreceived in said larger holes, threaded shanks on said bolts extendingthrough said smaller holes, heads on said bolts adjacent said collars,nuts screwed on the ends of said shanks and an eccentric on the boltpassing through said transverse slot and disposed in said transverseslot, the shanks of the other bolts being received in said longitudinalslots and being slidable along the same, the shanks of all of said boltsbeing of the same diameter, the larger holes being all of the samediameter and substantially equal to the diameter of said collar andreceiving said collars and the smaller holes being substantially equalto the diameter of said shanks and receiving said shanks, and means forsecuring said plates to the flange of the upper chord of said otherjoist section.

7. In an adjustable joist, two joist sections disposed end to end, eachincluding upper and lower chords, a connection for adjustably connectingthe lower chords of the sections together, the upper chords of saidsections having aligning longitudinally extending flanges thereon, theflange of one of said upper chords having a transverse slot and aplurality of longitudinal slots, said slots being spaced equal distancesfrom one another, plates overlying both of said flanges and disposed oneon each side thereof, said plates having circular holes thereinregistering with the various slots in said flanges, the holes in one ofsaid plates being greater in diameter than the holes in the other plate,a bolt extending through said transverse slot and through the holesregistering therewith, other bolts extending through the otherregistering holes and slots, collars formed on all of said bolts andreceived in said larger holes, threaded shanks on said bolts extendingthrough said smaller holes, heads on said bolts adjacent said collars,nuts screwed on the ends of said shanks and an eccentric on the boltpassing through said transverse slot and disposed in said transverseslot, the shanks of the other bolts being received in said longitudinalslots and being slidable along the same, the shanks of all of said boltsbeing of the same diameter andthe collars of all of said bolts being ofthe same diameter, the larger holes being all of the same diameter andsubstantially equal to the diameter of said collar and receiving saidcollars and the smaller holes being substantially equal to the diameterof said shanks and receiving said shanks, said eccentrics being of aradius substantially equal to the eccentricity plus the radius of saidshank and said collars being of radius substantially equal to theeccentricity plus the radius of said eccentric, and means for securingsaid plates to the flange of the upper chord of said other joistsection.

8. In an adjustable joist, two joint sections disposed end to end, eachincluding upper and lower chords, a connection for connecting the lowerchords of the section together, the upper chord of one of said sectionshaving a part formed with a'transverse slot therein, a clamp memberoverlying said part and secured to the upper chord of the other trusssection, and a cam rotatable relative to said clamp member and extendingthrough said slot, said cam engaging a Wall of said part at the slot toshift the ends of the upper chords relative to one another in alongitudinal direction and clamping means for clamping said clamp memberand part together.

9. A connection comprising an elongated plate-like first part and asecond part disposed at the end of the first part, plates on oppositesides of and overlying said first part and secure to said second part,said first part having a tranverse slot therein near the end thereof anda plurality of longitudinally extending slots disposed outwardly of saidtransverse slot and in alignment therewith, the centers of all of saidslots being equally spaced, said plates each having a series of aligningholes therein spaced apart the same distance as the spacing of saidslots, the holes in one of said plates being all substantially the samediameter and the holes in the other of said plates being allsubstantially the same diameter and lesser in diameter than those in thefirst named plate, an eccentric disposed in 'the transverse slot andhaving a collar adapted to be rotatably mounted in any of a number ofsaid larger holes, and bolts extending through said holes and certain ofsaid longitudinal slots, said bolts having collars received within saidlarger holes, and shanks extending through said longitudinal slots andthrough said smaller holes, heads on the ends of the said bolts adjacentsaid collars and disposed adjacent the plate in which the larger holesare formed and nuts on said shank reacting against the other of saidplates.

10. A connection comprising an elongated plate-like first part and asecond part disposed at the end of said first part, plates overlyingsaid first part on opposite sides thereof and secured to said secondpart, said first part having a transverse slot therein near the endthereof and a plurality of longitudinally extending slots disposedoutwardly of said transverse slot and in alignment therewith, thecenters of all of said slots being equally spaced, said plates eachhaving a series of aligning circular holes therein registering with oneanother and with said slots, the holes in each plate being ofsubstantially the same diameter and the holes in one plate being greaterin diameter than the holes in the other plate, a bolt extending throughthe transverse slot and the holes registering therewith, said bolthaving a head disposed adjacent to the plate having the larger hole, acollar on said bolt received in the larger hole, an eccentric on saidbolt disposed within said transverse slot, a threaded shank extendingoutwardly from said eccentric, coaxially disposed with reference to saidcollar and extending through said smaller hole, a nut screwed on the endof said shank, said nut and bolt holding said eccentric in adjustedposition and assisting in clamping said plates in position on saidflange and other clamping means acting between said plates and utilizingsaid longitudinal slots and the holes registering therewith for furtherclamping said plates in position on said first part.

11. A connection comprising an elongated plate-like first part and asecond part disposed at the end of the first part, plates on oppositesides of and overlying said first part and secured to said second partsaid first part having a transverse slot therein near the end thereofand a plurality of longitudinally extending slots disposed outwardly ofsaid transverse slot and in alignment therewith, said longitudinal slotsbeing of a width less than the transverse slot, the centers of all ofsaid slots being equally spaced, said plates each having a series ofaligning holes therein spaced apart the same distance as the spacing ofsaid slots, the holes in one of said plates being all substantially thesame diameter and substantially equal in diameter to the width of saidlongitudinal slots, and the holes in the other of said plates being allsubstantially the same diameter and greater in diameter than the widthof said transverse slot, an eccentric disposed in the transverse slotand having a collar adapted to be rotatably mounted in any of a numberof said larger holes, and bolts extending through said holes and certainof said longitudinal slots, said bolts having collars received withinsaid larger holes, and shanks extending through said longitudinal slotsand through said smaller holes, heads on the ends of the said boltsadjacent said collars and disposed adjacent the plate in which thelarger holes are formed and nuts on said shank reacting against theother of said plates.

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